Abstract
In this paper we present the first example of waveguides fabricated by UV writing in non-hydrogen loaded Ge-doped planar silica with 213 nm light. Single mode waveguides were fabricated and the numerical apertures and mode field diameters were measured for a range of writing fluences. A peak index change of 5.3 x 10-3 was inferred for the waveguide written with 70 kJ cm-2. The refractive index change is sufficient to match the index structure of standard optical fiber. Uniformity of the written structures was measured and a propagation loss of 0.39 ± 0.03 dB cm-1 was determined through cutback measurements.
Highlights
Integrated optical waveguides and circuits have a wide range of applications, including; sensing [1,2,3,4], and quantum technologies [5,6,7] to name but a few
The work in this paper was inspired by the achievement of strong fiber Bragg gratings (FBGs) in Ge-doped optical fiber without prior hydrogen loading by using a nanosecond pulsed UV laser operating at 213 nm [31]
The numerical aperture (NA) and mode field diameter (MFD) of each waveguide written with different fluences are compared and the resulting index change induced by the UV light is inferred
Summary
Integrated optical waveguides and circuits have a wide range of applications, including; sensing [1,2,3,4], and quantum technologies [5,6,7] to name but a few. Photonic structures can be created in planar doped silica without the need for etching by inducing a local refractive index change through exposure to a focused UV laser beam, as shown in figure 1(a) This technique has been used for phase tuning of optical devices [13] and to produce planar integrated circuits [14,15,16,17]. UV fabrication of integrated silica photonics relies on the photosensitivity provided by doping with Germanium, Phosphorous and Boron It is usually necessary for in-diffusion of hydrogen or deuterium prior to UV writing to produce a refractive index change sufficient to form waveguides [19]. These effects can cause variation of the final written structures and these issues scale with device complexity, something undesirable in applications such as quantum technology and sensing, which require device consistency and compact, integrated solutions [6, 23]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
